The present invention relates to a direct-alcohol fuel-cell stack.
Fuel cells are electrochemical devices capable of converting the chemical energy contained in a fuel into electrical direct current, in the absence of moving parts.
Said electrochemical device comprises an anode and a cathode separated by an electrolyte, i.e., a substance that enables migration of the ions. In order to favour the electrochemical reactions it is necessary to use appropriate catalysts, for example platinum.
The cell is supplied with the fuel (typically hydrogen or another molecule containing hydrogen) and with an oxidant (typically oxygen or air), which, electrochemically combined, generate electricity and produce water as waste product.
The individual cells, characterized by voltages comprised between half a volt and one volt according to the technology adopted, can be connected in series, so as to obtain a total voltage of the desired value. Said arrangement of the cells forms the so-called fuel-cell stack, to which there can be associated an inverter and a transformer for converting the direct current generated by the stack of cells into alternating current at the desired voltage and at the desired frequency.
Development of fuel cells and of their applications is currently retarded to a large extent by the production costs involved, which are still high, and by certain technological and manufacturing problems.
In this perspective, it should for example be noted that the traditional systems of production of electrode structures for fuel cells are based upon the deposition of catalysts on carbon substrates, hot-pressed on an electrolyte in the form of a membrane. The said technique has proven costly.
Current fuel cells suffer, moreover, from a certain slowness of operation in the step of start-up of the electrochemical process, and this precludes their use in those applications that entail an immediate generation of electrical energy.